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CryptoHack

A fun, free platform for learning modern cryptography

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Learn By Doing

Learn about modern cryptography by solving a series of interactive puzzles and challenges. Get to know the ciphers and protocols that secure the digital world by breaking them.

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Level Up

Earn points by solving challenges. Finish categories to earn trophies and gain levels to track your progress. Can you reach the top of the scoreboard?

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Fresh Challenges

We are constantly creating new challenges to keep your crypto knowledge up to date. Expect exciting brainteasers and whole new categories as the site continues to grow.

New Challenges
Unimplemented CTF Archive 0
Unevaluated CTF Archive 0
Calm Down CTF Archive 0
2020 CTF Archive 0
Key recovery CTF Archive 0
Weekly Top Users
#1 jazzzooo 4250
#2 Xavier07 2730
#3 placwmr 2680
#4 magnuel14 2655
#5 samael98 2573
Recent Solves
Modular Arithmetic 2 y4y
Curveball placwmr
Diffie-Hellman Starter 1 Trefoil
RSA Backdoor Viability Generate
Finding Flags Ojun
Recent Solutions
SpongeBob SquarePants / Battle for Bikini Bottom - Rehydrated Robin_Jadoul 0
Passwords as Keys HIGH0101 0
Greatest Common Divisor joemclean 0
No Leaks Kioku 0
Bruce Schneier's Password mathno1 0

Level Up

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